Printing devices which utilize a removable plate, such as a credit card, of the aforementioned kind, are well known in the art, as exemplified in the German patent DT-PS 1,279,034. Such printing devices usually have a carriage made up of two arms. One arm extends forwardly from the middle area of the carriage, through which area a slide rod is received, and serves as a printing arm by supporting a printing roll. The second arm, which extends substantially into the opposite backward direction, bears a guide roller which cooperates with a guide rod extending parallel to the slide rod and mounted in the housing. In this type of machine, all the forces of reaction resulting from action on a printing anvil by the printing roll are absorbed by the carriage, by the slide rod, the guide rod, and the housing bearing both these rods. As a consequence, it is essential to use a relatively sturdy and rigid carriage slide rod, guide rod and housing, to afford reliable operation over extended periods of use. For this purpose, all the essential parts of the device, particularly the carriage, have to be made out of castings. This results in a relatively expensive and heavy device in order to obtain the required endurance.